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Solution of the Center Problem for a Class of Polynomial Differential Systems

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1685-1696页

作者： Chang Jian Liu Jaume Llibre Rafael ramírez Valentín ramírez School of Mathematics(Zhuhai) Sun Yat-sen UniversityZhuhai519086P.R.China Departament de Matemàtiques Universitat Autònoma de Barcelona08193BellaterraBarcelonaCataloniaSpain Departament d’Enginyeria Informàtica i Matemàtiques Universitat Rovira i VirgiliAvinguda dels Paiïsos Catalans 2643007TarragonaCataloniaSpain

Consider the polynomial differential system of degree m of the form x=-y(1+μ(a_(2)x-a_(1)y))+x(v(a_(1)x+a_(2)y)+Ω_(m-1)(x,y)),y=x(1+μ(a_(2)x-a_(1)y))+y(v(a_(1)x+a_(2)y)+Ω_(m-1)(x,y)),whereμandνare real numbers such that(μ^(2)+v^(2))(μ+v(m-2))(a_(1)^(2)+a_(2)^(2))≠m>2 andΩ_(m−1)(x,y)is a homogenous polynomial of degree m−1.A conjecture,stated in J.Differential Equations 2019,suggests that whenν=1,this differential system has a weak center at the origin if and only if after a convenient linear change of variable(x,y)→(X,Y)the system is invariant under the transformation(X,Y,t)→(−X,Y,−t).For every degree m we prove the extension of this conjecture to any value ofνexcept for a finite set of values ofμ.

关键词： Center problem polynomial differential system

Development of novel 5-FU modified siRnA against BCL-2 with enhanced efficacy and vehicle-free cellular uptake

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Genes & Diseases 2024年第1期11卷 23-25页

作者： Andrew Fesler Ga-ram Hwang Jingfang Ju Department of Pathology Renaissance School of MedicineStony Brook UniversityStony BrookNY 11794USA The northport Veteran's Administration Medical Center NorthportNY 11768USA Curamir Therapeutics Inc. WoburnMA 01801USA

One of the major obstacles for nucleic acid-based medicine is cellular uptake due to the concern of efficiencyand potential toxicity of the vehicle.In this work,we developed a novel approach to eliminate the need for a vehicle to allow for the cellular uptake of siRnA-based therapy with a unique modification strategy that also further enhances therapeutic efficacy.This discovery may be of great importance for the development of siRnA-based therapeutics as cellular uptake remains a critical challenge.In this study,we have tested the potential of this modification strategy for siRnA using a siRnA that targets B-cell lymphoma-2(BCL-2).

关键词： eliminate uptake modified

Impacts of PI3K/protein kinase B pathway activation in reactive astrocytes: from detrimental effects to protective functions

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neural Regeneration Research 2025年第4期20卷 1031-1041页

作者： ramón Pérez-núñez María Fernanda González Ana María Avalos Lisette Leyton Cellular Communication Laboratory Programa de Biología Celular y MolecularCenter for Studies on ExerciseMetabolism and Cancer(CEMC)Instituto de Ciencias Biomédicas(ICBM)Facultad de MedicinaUniversidad de ChileSantiagoChile Advanced Center for Chronic Diseases(ACCDiS) Faculty of Chemical and Pharmaceutical Sciences&Faculty of MedicineUniversidad de ChileSantiagoChile Instituto de Ciencias Biomédicas Facultad de Ciencias de la SaludUniversidad Autónoma de ChileSantiagoChile

Astrocytes are the most abundant type of glial cell in the central nervous system.Upon injury and inflammation,astrocytes become reactive and undergo morphological and functional changes.Depending on their phenotypic classification as A1 or A2,reactive astrocytes contribute to both neurotoxic and neuroprotective responses,respectively.However,this binary classification does not fully capture the diversity of astrocyte responses observed across different diseases and injuries.Transcriptomic analysis has revealed that reactive astrocytes have a complex landscape of gene expression profiles,which emphasizes the heterogeneous nature of their reactivity.Astrocytes actively participate in regulating central nervous system inflammation by interacting with microglia and other cell types,releasing cytokines,and influencing the immune response.The phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT)signaling pathway is a central player in astrocyte reactivity and impacts various aspects of astrocyte behavior,as evidenced by in silico,in vitro,and in vivo results.In astrocytes,inflammatory cues trigger a cascade of molecular events,where nuclear factor-κB serves as a central mediator of the pro-inflammatory responses.Here,we review the heterogeneity of reactive astrocytes and the molecular mechanisms underlying their activation.We highlight the involvement of various signaling pathways that regulate astrocyte reactivity,including the PI3K/AKT/mammalian target of rapamycin(mTOR),αvβ3 integrin/PI3K/AKT/connexin 43,and notch/PI3K/AKT pathways.While targeting the inactivation of the PI3K/AKT cellular signaling pathway to control reactive astrocytes and prevent central nervous system damage,evidence suggests that activating this pathway could also yield beneficial outcomes.This dual function of the PI3K/AKT pathway underscores its complexity in astrocyte reactivity and brain function modulation.The review emphasizes the importance of employing astrocyte-exclusive models to understand their functions accurately and these models

关键词： inflammation integrins neuroprotective neurotoxic phosphatidylinositol 3-kinase reactive astrocytes signal transduction Thy-1(CD90)

Seedling potential of trees species along the elevational gradient in temperate hill forest of central nepal

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Journal of Mountain Science 2024年第4期21卷 1329-1344页

作者： DAnI ram Sharan BAnIYA Chitra Bahadur Central Department of Botany Tribhuvan UniversityKirtipur 44618Nepal

Regeneration status of tree species along elevation gradient in temperate hill forest was not understood greatly.Present research examined the tree diversity and its regeneration patterns along an elevation gradient in temperate hill forest,central nepal.Data were collected from 300 sample plots within vertical elevation bands of 10,ranging from 1365 to 2450 m asl.A random sampling method was used for data collection in three seasons,winter,pre-monsoon and post monsoon seasons.Diameter at breast height(DBH)was used to broadly categorize the plant individual into trees,saplings and seedlings.The tree species richness ranged from 12 to 25 with density of 350 to 1200 individuals per hectare.Species richness of tree and sapling showed statistically significant unimodal pattern,which peaked at mid-elevation.Elevation showed a strong and positive linear correlation with the seedling density(Deviance=0.99,pnd a significant hump-shaped relationship with sapling density(Deviance=0.95,pns showed a statistically significant negative hump-shaped relationship with all trees,saplings and seedling stages(Deviances=0.89,0.87 and 0.57).The highest values of the Shannon-Wiener index and the lowest value of the Simpson index were found at mid-elevation for all growth forms.nearly 92%of tree species were found at regenerating stage;49%in a good renewal regeneration status,32%in fair renewal regeneration,and 11%at a poor regenerating condition.nevertheless,4%of tree species were reported as non-regenerating stages and 4%were newly introduced species.Hence,the regeneration status of the study area was considered fairly well since sapling(78.5%)>seedling(10.6%)≤mature(10.9%).Among tested environmental variables,elevation and annual mean rainfall were the most influential factors in the regeneration of tree species.

关键词： Regeneration potential Chandragiri hill Altitudinal gradient Species diversity Tree species richness

From prediction to prevention:Machine learning revolutionizes hepatocellular carcinoma recurrence monitoring

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World Journal of Gastroenterology 2024年第7期30卷 631-635页

作者： Mariana Michelle ramírez-Mejía nahum Méndez-Sánchez Plan of Combined Studies in Medicine Faculty of MedicineNational Autonomous University of MexicoDistrito Federal 04510Mexico Liver Research Unit Medica Sur Clinic&FoundationDistrito Federal 14050Mexico Faculty of Medicine National Autonomous University of MexicoDistrito Federal 04510Mexico

In this editorial,we comment on the article by Zhang et al entitled Development of a machine learning-based model for predicting the risk of early postoperative recurrence of hepatocellular carcinoma.Hepatocellular carcinoma(HCC),which is characterized by high incidence and mortality rates,remains a major global health challenge primarily due to the critical issue of postoperative recurrence.Early recurrence,defined as recurrence that occurs within 2 years posttreatment,is linked to the hidden spread of the primary tumor and significantly impacts patient survival.Traditional predictive factors,including both patient-and treatment-related factors,have limited predictive ability with respect to HCC recurrence.The integration of machine learning algorithms is fueled by the exponential growth of computational power and has revolutionized HCC research.The study by Zhang et al demonstrated the use of a groundbreaking preoperative prediction model for early postoperative HCC recurrence.Challenges persist,including sample size constraints,issues with handling data,and the need for further validation and interpretability.This study emphasizes the need for collaborative efforts,multicenter studies and comparative analyses to validate and refine the model.Overcoming these challenges and exploring innovative approaches,such as multi-omics integration,will enhance personalized oncology care.This study marks a significant stride toward precise,efficient,and personalized oncology practices,thus offering hope for improved patient outcomes in the field of HCC treatment.

关键词： Hepatocellular carcinoma Early recurrence Machine learning XGBoost model Predictive precision medicine Clinical utility Personalized interventions

Chemotherapy and radiotherapy:Could they contribute to the development of new tumors and metastases?

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Life Research 2024年第1期7卷 24-27页

作者： Joséramón Toro López An independent researcher Sevilla 41500Spain.

Objective: Both chemotherapy and radiotherapy have demonstrated high effectiveness as the best mechanisms in the fight against cancer;however, various studies seem to confirm that they could also favor the development of other unwanted effects of great importance for the patient. The main objective of this study is to find out the possible existence of this type of links. Method: This is a systematic literature review that seeks to find out which and how long cases of late interactions related to chemotherapy and radiotherapy treatments have been known. The bibliographic review was carried out based on references published in the last five years. Results: Various studies confirm the possible relationship between chemotherapy and radiotherapy treatments with the development of new undesirable side effects, especially as a consequence of the hepatotoxicity generated in the case of chemotherapy and radiation in radiotherapy. However, in this last type of treatment, the problems raised are really few. Conclusions: The existence of a risk of suffering new unwanted side effects after different types of treatment seems to have been demonstrated, especially in the case of chemotherapy. In the case of radiotherapy, adverse effects are practically non-existent, although they are no less important.

关键词： Chemotherapy radiotherapy tumor cancer metastasis hepatotoxicity radiation

Impact of STAT-signaling pathway on cancer-associated fibroblasts in colorectal cancer and its role in immunosuppression

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World Journal of Gastrointestinal Oncology 2024年第5期16卷 1705-1724页

作者： Damián Sánchez-ramírez Mónica G Mendoza-Rodríguez Omar R Alemán Fernando A Candanedo-González Miriam Rodríguez-Sosa Juan JoséMontesinos-Montesinos Mauricio Salcedo Ismael Brito-Toledo Felipe Vaca-Paniagua Luis I Terrazas Unidad de Investigacion en Biomedicina Facultad de Estudios Superiores IztacalaUniversidad Nacional Autonoma de MexicoTlalnepantla 54090Estado de MexicoMexico Department of Biology Facultad de QuimicaUniversidad Nacional Autonoma de MexicoCiudad UniversitariaMexico City 04510Mexico Department of Pathology National Medical Center Century XXIInstituto Mexicano del Seguro SocialMexico City 06720Mexico Laboratorio de Células Troncales Mesenquimales Unidad de Investigación Médica en Enfermedades OncológicasHospital de Oncología Centro Medico Nacional Siglo XXIInstituto Mexicano del Seguro SocialMexico City 06720Mexico Unidad de Investigacion en Biomedicina y Oncologia Genomica Instituto Mexciano del Seguro SocialMexico City 07300Mexico Servicio de Colon y Recto Hospital de Oncología Centro Medico Nacional Siglo XXIInstituto Mexicano del Seguro SocialMexico City 06720Mexico Laboratorio nacional en Salud Facultad de Estudios Superiores IztacalaUniversidad Nacional Autónoma de MéxicoTlalnepantla 54090Estado de MexicoMexico

Colorectal cancer(CRC)remains one of the most commonly diagnosed and deadliest types of cancer worldwide.CRC displays a desmoplastic reaction(DR)that has been inversely associated with poor prognosis;less DR is associated with a better prognosis.This reaction generates excessive connective tissue,in which cancer-associated fibroblasts(CAFs)are critical cells that form a part of the tumor microenvironment.CAFs are directly involved in tumorigenesis through different mechanisms.However,their role in immunosuppression in CRC is not well understood,and the precise role of signal transducers and activators of transcription(STATs)in mediating CAF activity in CRC remains unclear.Among the myriad chemical and biological factors that affect CAFs,different cytokines mediate their function by activating STAT signaling pathways.Thus,the harmful effects of CAFs in favoring tumor growth and invasion may be modulated using STAT inhibitors.Here,we analyze the impact of different STATs on CAF activity and their immunoregulatory role.

关键词： Cancer-associated fibroblasts Signal transducer and activator of transcription signaling Colorectal cancer Immunity Immunosuppression

Twenty years of population dynamics in European beech-oak forest at their rear range margin anticipate changes in its structure and composition

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Forest Ecosystems 2024年第3期11卷 358-370页

作者： álvaro Rubio-Cuadrado Iciar Alberdi Isabel Canellas Fernando Montes Jesús Rodríguez-Calcerrada Rosana López Guillermo G.Gordaliza María Valbuena-Carabana nikos nanos ramón Perea Luis Gil Departamento de dinamica y gestion forestal Instituto de Ciencias Forestales(ICIFOR-INIA)CSICCtra.La Coruna km 7.528040MadridSpain Departamento de Sistemas y Recursos naturales Escuela Tecnica Superior de Ingeniería de MontesForestal y del Medio NaturalUniversidad Politecnica de Madrid.Ciudad Universitaria s/n28040MadridSpain School of Forestry and natural Environment Aristotle University of ThessalonikiUniversity Campus54124ThessalonikiGreece

There is an increasing interest in restoring degraded forests,which occupy half of the forest areas.Among the forms of restoration,passive restoration,which involves the elimination of degrading factors and the free evolution of natural dynamics by applying minimal or no management,is gaining attention.natural dynamics is difficult to predict due to the influence of multiple interacting factors such as climatic and edaphic conditions,composition and abundance of species,and the successional character of these species.Here,we study the natural dynamics of a mixed forest located in central Spain,which maintained an open forest structure,due to intensive use,until grazing and cutting were banned in the 1960s.The most frequent woody species in this forest are Fagus sylvatica,Quercus petraea,Quercus pyrenaica,Ilex aquifolium,Sorbus aucuparia,Sorbus aria and Prunus avium,with contrasting shade and drought tolerance.These species are common in temperate European deciduous forest and are found here near their southern distribution limit,except for Q.pyrenaica.In order to analyze forest dynamics and composition,three inventories were carried out in 1994,2005 and 2015.Our results show that,despite the Mediterranean influence,the natural dynamics of this forest has been mainly determined by different levels of shade tolerance.After the abandonment of grazing and cutting,Q.pyrenaica expanded rapidly due to its lower shade tolerance,whereas after canopy closure and forest densification,shade-tolerant species gained ground,particularly F.sylvatica,despite its lower drought and late-frost tolerance.If the current dynamics continue,F.sylvatica will overtake the rest of the species,which will be relegated to sites with shallow soils and steep slopes.Simultaneously,all the multi-centennial beech trees,which are undergoing a rapid mortality and decline process,will disappear.

关键词： Forest succession Secondary forest Woodland Mixed forest Competition Recruitment

nanoparticle Exsolution on Perovskite Oxides:Insights into Mechanism,Characteristics and novel Strategies

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nano-Micro Letters 2024年第2期16卷 312-346页

作者： Yo Han Kim Hyeongwon Jeong Bo‑ram Won Hyejin Jeon Chan‑ho Park Dayoung Park Yeeun Kim Somi Lee Jae‑ha Myung Department of Materials Science and Engineering Incheon National UniversityIncheon 22012Republic of Korea

Supported nanoparticles have attracted considerable attention as a promising catalyst for achieving unique properties in numerous applications,including fuel cells,chemical conversion,and batteries.nanocatalysts demonstrate high activity by expanding the number of active sites,but they also intensify deactivation issues,such as agglomeration and poisoning,simultaneously.Exsolution for bottomup synthesis of supported nanoparticles has emerged as a breakthrough technique to overcome limitations associated with conventional nanomaterials.nanoparticles are uniformly exsolved from perovskite oxide supports and socketed into the oxide support by a one-step reduction process.Their uniformity and stability,resulting from the socketed structure,play a crucial role in the development of novel nanocatalysts.Recently,tremendous research efforts have been dedicated to further controlling exsolution particles.To effectively address exsolution at a more precise level,understanding the underlying mechanism is essential.This review presents a comprehensive overview of the exsolution mechanism,with a focus on its driving force,processes,properties,and synergetic strategies,as well as new pathways for optimizing nanocatalysts in diverse applications.

关键词： Supported nanoparticle Exsolution In situ growth Mechanism Perovskite oxide Catalyst